1. Field of the present invention
The present invention relates to fire door locks, and, more particularly, to a fire door lock which allows a user to easily push forward to open a fire door mounted with the fire door lock.
2. Description of Related Art
A conventional fire door, as shown in FIG. 1, is opened by pressing a handle 11 of a handle frame base 10 horizontally located in the middle of the fire door, whereby a locking bolt 12d in a lock housing 12 is retracted and relieves a locked state that closes and locks the fire door and the fire door is opened. This operation is achieved by a diagonal depression motion of the handle 11 which is pressed by a user to move in a downward and diagonal direction.
Please refer to FIGS. 2 and 3, which show a conventional fire door lock that is rotated by 90 degrees and oriented in a horizontal direction for clear illustration. The handle frame base 10 houses a pressing handle 11 that allows a user to press downwards and a lock housing 12 that accommodates a locking bolt 12d. The pressing handle 11 is screwed to two fixing seats 13 located at the bottom of the handle frame base 10. A roller sliding pillar 13b penetrates through two slanted slots 13a respectively formed on two side walls of each of the fixing seats 13, and is fixed to the side walls of the fixing seats 13 by means of a shim 13c. A pin 13e having a wound elastic member 13d thereon is secured to the bottom of each of the fixing seats 13. One end of the elastic member 13d is in contact with the bottom of the roller sliding pillar 13b on which an upward compression force is exerted.
Under a normal condition, the shim 13c of the roller sliding pillar 13b holds the handle 11 in position at the top of the handle frame base 10. When the user exerts a force on the handle 11, the roller sliding pillar 13b is pushed downwards and travels along the slots 13a of each fixing seat 13 by the force, thereby inducing diagonal translocation of the handle 11 in the handle frame base 10.
The lock housing 12 located at the front of the handle frame base 10, shown in FIG. 3, comprises a seesaw lever 12a which is constructed by coupling a push part 12b and a pull part 12c, wherein the push part 12b is in contact with an inside surface of the handle 11 and the pull part 12c is engaged with a cavity 12e formed by the locking bolt 12d in the lock housing 12. When the user presses the handle 11, the push part 12b of the lever 12a is pushed downwards while the pull part 12c is moved upwards. At the same time, the pull part 12c comes into contact with the locking bolt 12d which is driven to rotate in a counterclockwise direction, making the locking bolt 12d retracted into the lock housing 12 to facilitate a door opening action.
In view of the above door opening operation in the use of the conventional fire door lock, although the user presses the handle 11 in a manner as illustrated in FIG. 3, the handle 11 is moved in a diagonal direction by the roller 13b traveling along the slots 13a of each fixing seat 13 in the handle frame base 10. The diagonal movement of the handle 11 is composed of a vertical movement and a horizontal movement. The force exerted by the user is undesirably divided into two components: a force vertical to the push part 12b and used for operating the locking bolt 12d, and a force horizontal to the push part 12b and having no contribution to the locking bolt 12d, which therefore requires a larger amount of force exerted by the user due to wastage. Further, the horizontal movement of the handle 11 makes the travel direction of the handle 11 different from that of the hands of the user, which causes discomfort to the hands of the user when operating the door lock.
Furthermore, when the conventional fire door lock is used in a fire accident, because there is no fire protection elements mounted in the fire lock, and the door lock does not have to prevent from opening, it is likely that a person, who does not realizes the fire condition, may mistakenly open the fire door lock, resulting in injuries and death caused by the fire, and the fire may start to spread. Therefore, a novel, improved fire door lock which can eliminate the above drawbacks is greatly desired.